JPH0350979Y2 - - Google Patents

Description

[Detailed description of the invention] The invention has good water resistance and chemical resistance,
This invention relates to an easily incinerated liquid sample container. Glass beakers have traditionally been most commonly used as containers for liquid samples in various chemical experiments, water quality tests, etc. Containers for collecting various liquid tests for purposes such as urinalysis are also used in hospitals and the like. In recent years, containers made of paper and disposable containers have been introduced to streamline cleaning.
Those made of synthetic resin or a laminate made of paper and synthetic resin are often used. however,
Paper cups are lightweight and have excellent incineration properties, but are rarely used as containers for liquid samples because of their poor water resistance. Therefore, laminates made of paper coated or laminated with synthetic resin have been proposed as an alternative container material to paper. This laminate improves water resistance to some extent, but in addition to the manufacturing process of the laminate, it requires an adhesion process to manufacture the container, just like paper containers, resulting in low productivity and the presence of adhesive parts, making it safe. There were also problems with sexuality. For this reason, containers made of synthetic resins such as polystyrene and polyolefin are widely used. However, although these synthetic resin containers have excellent processability, light weight, and hygiene, they burn significantly more calories than paper when incinerating waste, and they may damage the incinerator wall or melt and solidify. There are disadvantages such as causing In addition, because the surface is smooth, it is impossible to write the name of the collected sample with a pencil, and because it is lightweight, it lacks stability and has poor strength, rigidity, and solvent resistance.
It also lacks sufficient heat resistance, which greatly limits its field of use. Therefore, the present inventors developed a container for liquid samples that burns low calories, has good water resistance, chemical resistance, heat resistance, strength, etc., allows writing on the surface with a pencil, and has a sense of stability. As a result of intensive research, they found that a container made of a specific material satisfies the purpose, and completed the invention. That is, the present invention provides a polyolefin resin which is made of a mixture of polypropylene resin and polyethylene resin, and whose mixing ratio is polypropylene resin: polyethylene resin = 7:3 to 3:7 (weight ratio). On the other hand, for liquid samples made of a polyolefin resin material, which is made by blending talc with an average particle size of 5 to 30μ in a proportion of 20 to 70% by weight of the entire composition and titanium oxide in a proportion of 1 to 10% by weight of the whole composition. It is a container. As mentioned above, the polyolefin resin in the present invention is a mixture of polypropylene resin and polyethylene resin. Examples of the polypropylene resin include propylene homopolymers, block copolymers and random copolymers of propylene and 30% by weight or less of other α-olefins such as ethylene, and mixtures thereof. In addition, the melt index of this polypropylene resin is generally
0.1 to 5 g/10 minutes, preferably 0.2 to 3 g/10 minutes,
More preferably, it is 0.3 to 1.5 g/10 minutes.
In this case, the melt index is 5g/
If the melting time exceeds 10 minutes, the melt strength of the sheet will be low, while if it is less than 0.1g/10 minutes, the fluidity will be poor, and the uniform kneading ability with talc will not be sufficient, resulting in poor secondary formability such as thermoforming. becomes difficult. On the other hand, there are various types of polyethylene resins, such as high-density polyethylene, medium-density polyethylene, and low-density polyethylene.
There are random or block copolymers with up to 30% by weight of other α-olefins (such as propylene). Here, the density of high-density polyethylene is
0.940 to 0.970 g/cm ³ , medium- and low-density polyethylenes include high-pressure polyethylene, ethylene and propylene obtained by medium- and low-pressure methods, butene-1,
There is a so-called linear low density polyethylene (LLDPE), which is a copolymer with an α-olefin having 3 to 12 carbon atoms such as 4-methylpentene-1 and octene-1. The melt index of this polyethylene resin is usually 0.02 to 10.0 g/10 minutes, preferably 0.03 to 5.0 g/10 minutes, and more preferably 0.04 to 10.0 g/10 minutes.
It is 2.0g/10 minutes. If the melt index of the polyethylene resin is outside the above range, it is unfavorable in terms of melt-kneading sheet formability and secondary formability such as thermoforming. In the present invention, a mixture of polypropylene resin and polyethylene resin is used as described above in order to continuously produce large quantities of lightweight deep containers by secondary forming such as vacuum forming and pressure forming.
The mixing ratio of polypropylene resin and polyethylene resin in this mixture is former: latter = 7:3
~3:7 (weight ratio). Next, although the type of talc used in the present invention is not particularly limited, it has an average particle size of 5 to 5.
30μ, preferably 10-20μ hydrated magnesium silicate, its composition is _SiO2 50-65%, MgO25
Burning weight loss 1 with ~40% and other ingredients
% or less. The blending ratio of this talc is determined in the range of 20 to 70% by weight, preferably 30 to 60% by weight of the entire composition. If the amount of talc is too large, the rigidity and incineration properties will improve, but the melt kneading, sheet formability, and secondary formability such as thermoforming will deteriorate. Furthermore, as described above, various types of talc can be used, and for example, highly purified talc or talc treated with acid to remove impurities can also be used. Note that this talc does not require any additional means such as surface treatment. Further, in the present invention, titanium oxide is used.
Here, titanium oxide is usually titanium dioxide (TiO ₂ )
However, it may also be mixed with a small amount of titanium monoxide (TiO) or dititanium trioxide (Ti ₂ O ₃ ). The shape of the titanium oxide is not particularly limited, but it is generally in the form of granules or powder with an average particle size of about 0.05 to 2 μm, preferably about 0.1 to 1 μm. When adding this titanium oxide, the mixing ratio should be such that, for example, when a 1 mm thick sheet is formed from the composition, the total light transmittance of this sheet is 3% or less, especially 2% or less. It is preferable that, specifically,
Containers for 1 to 10 liquid samples of the entire composition are suitable. The liquid sample container of the present invention is made of the above three components: polyolefin resin, talc, and titanium oxide, but if necessary, resins such as polyolefin modified with pigments, unsaturated carboxylic acids or derivatives thereof, rubber, and commonly used additives are used. Agents, etc. can be blended. The above polyolefin resin, talc, titanium oxide and desired components are thoroughly kneaded using a normal kneading method, that is, a roll, a Banbury mixer, a single screw extruder, a multi-screw extruder, etc., and then by a calender method, a T-die method, etc. Form into a sheet. Next, the thus obtained polyolefin resin sheet is formed into a liquid sample container by secondary thermoforming such as vacuum forming or pressure forming. By adopting this molding method, many pieces can be molded at once, the molding cycle is short, and continuous mass production is possible. Note that the thickness of the sheet is usually 0.2 to 3 mm. Furthermore, the liquid sample container of the present invention has a height/
The average diameter is 0.8 to 2.0, more preferably 1.0 to 1.8. As mentioned above, the container of the present invention is made by thermoforming a polyolefin resin sheet made of polyolefin resin, talc, and titanium oxide, so it does not reduce melt kneading properties and has sufficient melt strength. A deep container is obtained. Therefore, a container having a height/average diameter within the above range and suitable as a liquid sample container can be obtained. Regarding the shape of the container, it may be cylindrical or may expand from the bottom of the container toward the opening.
Furthermore, an undercut may be provided around the bottom edge of the container. The liquid sample container thus obtained has the following excellent properties. That is, it is easily incinerated and burns a low calorie when incinerated, so there is no damage to the furnace wall and no melting and solidification. It has high strength and good rigidity, heat resistance, water resistance, and chemical resistance.
You can write on the surface with a pencil, and the surface has good writing properties. It has a high specific gravity and is stable. It is odorless, does not elute talc, and has little effect on liquid samples. High concealment power. Excellent productivity. Therefore, it is expected that the liquid sample container of the present invention will be effectively used as a variety of disposable liquid sample containers such as beaker substitute containers and urinalysis containers. Next, the present invention will be explained with reference to examples. Example 1 Polypropylene homopolymer (density 0.91g/
cm ³ , melt index (MI) 0.6g/10min) 25
Weight%, high density polyethylene (density 0.964g/ ^cm3 ,
MI0.4g/10min) 25% by weight, 46% by weight of talc with an average particle size of 15μ, and 4% by weight of titanium oxide were melt-kneaded using a Banbury mixer to form pellets, and then made into a 1mm thick sheet using an extrusion molding machine. I got it. Next, a cup-shaped thermoformed product (height 90mm/ ^average diameter 60mm=
1.5) was manufactured. The resulting liquid sample container has the shape shown in Figure 1, with a bottom thickness of
The thickness of the bottom part was 0.85 mm, and the light transmittance according to ASTM D 1003 was 0.6%, and the thickness of the peripheral part was 0.36 mm, and the light transmittance of the peripheral part was 6.3%. The external appearance of this liquid sample container had the texture of high-quality paper and was full of luxury. The buckling strength of this liquid sample container is 19.5Kg, and the side compressive strength is 145
The whiteness of the outer surface of the container was 94.3%, and the glossiness GS (60°) was 6.0%. Note that the buckling strength was 18.5 kg and the side compressive strength was 160 g 10 minutes after filling the liquid sample container with water at 25°C. Furthermore, no abnormality was observed even after immersing the sample in boiling water at 95°C for 10 minutes. The calorie burn of this liquid sample container is 5430ca/
g, which was very low compared to 9860ca/g for HIPS cups and close to 4500ca/g for paper cups. Examples 2 to 7 and Comparative Examples 1 to 6 Cups were prepared in the same manner as in Example 1, except that the blending ratio of each component and the average particle size of talc were as shown in Table 1. A shaped thermoformed product (liquid sample container) was manufactured and its physical properties were evaluated. In addition, during the evaluation of physical properties, rigidity can be evaluated to some extent by buckling strength and side compressive strength. 【table】

Indicates buckling strength.
*4: Glossiness GS (60°) value

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an example of a liquid sample container according to the present invention.

Claims (1)

[Scope of utility model registration request] It is made of a mixture of polypropylene resin and polyethylene resin, and the mixing ratio is polypropylene resin: polyethylene resin = 7:3 ~
Talc with an average particle size of 5 to 30μ is added to the polyolefin resin at a ratio of 3:7 (weight ratio) to the entire composition.
20-70% by weight of titanium oxide and 1% of the total composition
A liquid sample container made of a polyolefin resin material mixed in a proportion of ~10% by weight.